It is known to use air ionisers in order to remove small particles from an environment. Typically after treatment, the particles are falling to the floor by gravity instead of continuously swirling around in the air causing respiratory problems. Such ionisers are commercially available and also known for use in special applications such as disclosed in U.S. Pat. No. 5,296,019, where a screen arrangement contains negative ion emitters in order to remove particles from an enclosed zone, for example around a dust producing machine. As disclosed in U.S. Pat. No. 5,296,019, the screens are dust proof in order to prevent the dust particles to leave the enclosed zone.
When particles are precipitated on the floor in such a zone, as disclosed in U.S. Pat. No. 5,296,019, movements in the zone may nevertheless lead to a swirling around of the particles. The particles are not removed from the environment. Furthermore, such a system is not suitable in a sleeping room, because falling allergenic particles such as pollen may be inhaled by an allergic person lying in a bed. Even further, even though air may penetrate the screens, the fine mesh of the screens for prevention of transport of dust across the screen allows a relatively small exchange of air between the inside and the outside of the enclosed environment.
There are on the other hand systems that remove particles by filtration. However, these systems are typically expensive and require a substantial amount of power due to an air fan for transportation of air through the system.
There is therefore a need for improvement, especially there is a need for a system which removes particles such as dust from the environment but which is simple, and cheap to produce.